Generally mobile communication systems are formed of a plurality of base stations that provide communication to a plurality of users distributed over an area. The area where the radio communication from the base station is in range is called a cell. The capacity and performance of wireless cellular system in a particular cell largely depends on antenna configuration of its base station.
Antenna tilt is one of the key configuration parameters for a base station. Antenna tilts are known to have significant impact on the capacity and quality of service in wireless cellular systems as they determine the direction and orientation of radio signal propagation and thus can control interference levels and overall performance and capacity of the wireless cellular system. The antenna needs to be adjusted at certain angle in order to adjust the coverage area of the base station antenna signals.
In current wireless cellular systems, the antenna tilts are updated manually either after laps of a fixed time period or only when significant performance reduction is observed. The conventional method to determine optimal tilting angle of antenna involve in-field drive tests to collect data which can be fed into an offline planning tool for determining a new tilt value based on heuristic calculations.
Such an exercise is a time consuming process and it requires skilled labor resources, thus making it expensive. Another disadvantage of this method is that, by the time new tilts of the antennas are configured, they can be already outdated. Hence, the antenna tilts in a wireless cellular system cannot be often set and maintained at optimal values.
The general methodology followed in conventional method of optimizing tilt angle of an antenna is by evaluating desired key performance indicators as a function of tilting angle of the antenna through a simulation model. A non exhaustive search is then carried out by exploration of the solution space in vicinities selected with the help of a heuristic method for obtaining the suitable tilt values. The problems of this method include the limited transparency of simulation model, inherent lack of guarantee of optimal value, and that the quality of outcome is hard to be asserted.
Further, the above method is time consuming and the reliance on offline planning tools thwarts practical implementation for tilting angle of an antenna in real time.
In addition to these drawbacks, no known methods of tilt optimization take into account generic scenarios of heterogeneous deployments where relay stations are deployed.
Therefore, there exists a need of improved means to effectively optimize and maintain antenna tilts autonomously in wireless cellular systems—homogeneous or heterogeneous—in response to their spatio-temporal dynamics that allows deeper insights and better control of the wireless cellular system for continuously maintaining optimal performance in a more transparent, secure, cost effective, and environment friendly manner.